Clouds Have A Heavier Energy Footprint Than Expected

The term cloud computing suggests an ethereal realm of software and data. But the servers, cooling systems, and back-up generators that undergird popular internet services remain stubbornly earthbound, and carry a heavy and growing energy footprint.

“They don’t get a bonus for saving on the electric bill. They get a bonus for having the data center available 99.999 percent of the time.”

Data centers now consumer 30 gigawatts worldwide, in part because computers are power-hungry and in part because they are used so inefficiently. Typical computer servers have a utilization rate of just 7 – 12%, and therefore draw most of their power while sitting idle.

This parallels the situation faced by buildings as a whole. Gridium’s analysis of our own customer base reveals that most buildings consume more energy when closed than when open, simply because they spend so much of their time unoccupied. Adding a data center into the mix intensifies this problem.

The following load curves show what a data center can do to a building’s energy consumption. Both are from well-managed office buildings in the same city, on the same week of the year. The building represented by the blue line lacks a data center and consumes about 108,000 kWh per week. The building represented by the red line has a similar amount of occupant-driven demand — about 600 kW difference between night and day. But because the second building has a data center, total weekly use is more than 170,000 kWh/week, 60% more than the building without a data center.

Particularly in buildings that aren’t owner-occupied, the facilities team often has little say over how data centers are managed. Nevertheless, several energy management strategies are worth exploring:

Move into the cloud. Although not appropriate for everyone, cloud computing does raise the enticing possibility of outsourcing infrastructure to a company with the proper resources and incentives to manage data centers more efficiently. Hybrid strategies are also a great way to avoid having to overprovision to meet peak computing demand.

Make sure tenant data centers are submetered. Even with proper incentives, most tenants won’t do a great job of managing their servers, but they absolutely should bear these costs.

Stop giving away cooling capacity. Many buildings will offer free condenser water to tenants with data centers. Not only is this a potentially expensive practice, it is a red flag to lease auditors, who might object on behalf of tenants that don’t enjoy this benefit.